Reset variables when changing SLOT

[matchbox]

Is it a reasonable practice to Reset variables on a SLOT before the new slot is entered?

I am using a 14M2 and want to use slot 0 and slot 1 as independent programs. Because of the way the change between the two takes place (on power up not power down), it isn't easy to do a reset before it leaves the previous slot.

 

[Hemi345]

You could write a byte to the PICAXE's EEPROM and check that on reset to determine which slot to run. That should be an easy way to reset all variables.

 

[inglewoodpete]

Is it a reasonable practice to Reset variables on a SLOT before the new slot is entered?

I am using a 14M2 and want to use slot 0 and slot 1 as independent programs. Because of the way the change between the two takes place (on power up not power down), it isn't easy to do a reset before it leaves the previous slot.

I think what you're asking for is the following code, which can be tested in the simulator. You could define it as a macro, so it can be invoked as a single line command in your code.

#PICAXE 14M2
'Open the Code Explorer prior to running this in the simulator
For b0 = 1 To 27 'For simulation, initialise b0 to b27 to non-zero values to demonstrate the zeroising code, further below
   Poke b0, b0
Next b0
' The following code zeros all byte registers and the bPtr
bPtr = 27
Do
   @bPtrDec = 0
Loop Until bPtr = 0
b0 = 0

 

[hippy]

I am using a 14M2 and want to use slot 0 and slot 1 as independent programs. Because of the way the change between the two takes place (on power up not power down), it isn't easy to do a reset before it leaves the previous slot.

It's not clear exactly how you will have things working but you could clear variables and/or RAM before you RUN another slot, or when the other slot starts. The second would be my preference.

 

[Aries]

Unless you are relying on variables (b0, w0 etc) being zero at the start of the program (which I would regard as bad practice anyway), it shouldn't be necessary to zero them, because the first reference to such a variable in any program should always be to load it with a value from somewhere else.

 

[matchbox]

Thank you all for the reply guys. That will do just fine Pete

It just uses a momentary switch to change Slots. Unfortunately this momentary switch is not on an interrupt pin, so it makes clearing more awkward before leaving a previous Slot.
The program has much mirrored code and variables, plus uses RF serial. So it needs many of the bytes and words cleared to prevent issues.

 

[PhilHornby]

You could write a byte to the PICAXE's EEPROM and check that on reset to determine which slot to run. That should be an easy way to reset all variables.

A variation on that theme, would be to set Bit 6 of the BORCON SFR, which @hippy documented in this thread:- https://picaxeforum.co.uk/threads/preserving-data-for-after-a-reset-command.29548/